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Abstract:

The present invention relates to a method for producing three-dimensional
objects based on computer-provided data, whereby a material is deposited
in layers in a process chamber and the material is selectively solidified
and/or bonded using a bonding apparatus and/or a solidifying apparatus in
the process chamber, these steps being repeated. A conveyance of the
material proceeds during the build process and proceeds continuously,
sequentially and evenly up to an unpacking position.

Claims:

1. A method for producing three-dimensional objects based on
computer-provided data comprising: depositing a material in layers in a
process chamber; selectively solidifying and/or bonding the materials
using a bonding apparatus and/or a solidifying apparatus in the process
chamber; and repeating the steps of depositing and solidifying and/or
bonding; wherein a conveyance of the material proceeds during the build
process and proceeds continuously, sequentially, and evenly up to an
unpacking position.

2. The method according to claim 1, wherein a conveyance direction
essentially remains up to the unpacking position.

3. The method according to claim 1, wherein a means for application for
the material and a deposited material layer are provided so that the
means for application and the material layer are moved toward each other
relatively for the application of a further material layer that a
reception plane of the material layer exhibits an angle of greater than
0.degree. to a layer plane of the means for application.

4. The method according to claim 1, wherein the solidifying apparatus
structures are created in the material layers, which impede slipping off
of the material layers during the build-up process.

5. The method according to claim 1, wherein the material is a powder
material, a film material, a fluid material, an extrusion material, a
dripped material, or a combination thereof.

6. The method according to claim 1, wherein first the particulate
material in a feedstock is introduced in a process chamber and then a
build process of an object begins on this particulate material feedstock.

7. The method according to claim 1, wherein created objects are unpacked
in the unpacking position without interrupting the build-up process.

8. The method according to claim 1, wherein solid material is deposited
in the form of thin films.

9. The method according to claim 8, wherein the films are connected to
each other by means of gluing and/or welding.

10. The method according to claim 1, wherein the conveyance continues
endlessly.

11. The method according to claim 1, wherein the material is moved via a
conveyance means.

12. The method according to claim 1, wherein the material is moved
horizontally.

13. The method according to claim 1, wherein material is moved with an
angle to horizontal.

14. A method for continuously producing three-dimensional objects
comprising: using computer-provided data, depositing a material on a
movable material reception means, forming an object or multiple objects
by repeatedly applying layers of the material on one side of the object
or multiple objects; subsequently solidifying and/or binding of the
material; and repeating the steps, wherein the object or objects on the
material reception means are continuously moved out of a process area
during the production process and unpacked on the material reception
means during the production process.

15. The method according to claim 14, wherein the layer plane exhibits an
angle of greater than 0.degree. to a reception plane of the reception
means.

16. A device for producing three-dimensional objects comprising;
computer-provided data, a material that is deposited in layers, a
solidifying apparatus that selectively solidifies, and a means to convey
the material during the build-up process continuously, sequentially, and
evenly up to an unpacking position.

17. The device according to claim 16, wherein a drive for layer
positioning can be a discontinuous switching device.

18. The device according to claim 16, wherein drop generator and/or a
radiation source is provided as a solidifying apparatus.

19. The device according to claim 16, wherein a spreader device and/or
the solidifying apparatus are moved on a coordinate system arranged at an
angle perpendicular to a reception plane of the reception means.

20. The method according to claim 2, wherein a means for application for
the material and a deposited material layer are provided so that the
means for application and the material layer are moved toward each other
relatively for the application of a further material layer that a
reception plane of the material layer exhibits an angle of greater than
0.degree. to a layer plane of the means for application.

Description:

[0001] The invention relates to a method for manufacturing
three-dimensional models as expressed in the generic concept of patent
claims 1 and 14 as well as a device as expressed in the generic concept
of patent claim 16.

[0002] A method for producing three-dimensional objects from computer data
is known from the prior art, for example, from the European patent
specification EP 0 431 924 B1. In the method described therein, a
particulate material is deposited in a thin layer onto a platform, and a
binder material is selectively printed on the particulate material, using
a print head. The particle area onto which the hinder is printed sticks
together and solidifies under the influence of the binder and, if
necessary, an additional hardener. The platform is then lowered by a
distance of one layer thickness into a build cylinder and provided with a
new layer of particulate material, which is also printed as described
above. These steps are repeated until a certain, desired height of the
object is achieved. A three-dimensional object is thereby produced from
the printed and solidified areas of the particulate material.

[0003] After it is completed, this object produced from solidified
particulate material is embedded in loose particulate material and is
subsequently removed from the process chamber and freed from loose
particulate material. This is done, for example, using an extractor. This
leaves the desired objects, from which the remaining particulate material
is removed, e.g. by brushing.

[0004] Other particulate material-supported rapid prototyping processes
work in a similar manner, such as, for example, selective laser sintering
or electron beam sintering, in which a loose particulate material is also
deposited in layers and selectively solidified with the aid of a
controlled physical radiation source.

[0005] All these methods are referred to collectively below as
"three-dimensional printing methods" or "3D printing methods".

[0006] All the mentioned embodiments have in common a detailed
manufacturing process for the desired products. The first step always
consists of generating a filled volume, which contains the components, in
the aforementioned process chamber. An example could be a powder
feedstock. Further individual sequentially ordered steps follow, such as
the removal of particulate material in order to obtain the desired final
components.

[0007] In various further publications, such as patents WO2004014637A1 or
U.S. Pat. No. 7,291,002 B2, at least the build process is considered and
a continuous operation for this purpose is suggested. Included in such is
that the build platform is continuously lowered and the layer application
is implemented in a screwing movement over the build area. However, in
addition to the high equipment costs, also with this method, only one
step is completed after termination of the build process. The removal of
the unbound particulate material proceeds again in a subsequent, separate
process.

[0008] The object of the invention is to provide a method and a device
with which it is possible to continuously carry out diverse work steps.

[0009] This object is achieved by a method according to patent claims 1
and 14 as well as a device according to patent claim 16.

[0010] According to one aspect of the present invention is a method for
producing three-dimensional objects, using a three-dimensional printing
method based on computer-provided data, whereby a material is deposited
in layers in a process chamber and the material is selectively solidified
and/or bonded using a bonding apparatus and/or a solidification apparatus
in the process chamber, these steps being repeated.

[0011] In hereby doing so, a conveyance of the first material proceeds
during the build process and proceeds continuously sequentially and
uniformly up to an unpacking position. Whereby "continuous" according to
the invention does not mean that the conveyance always takes place with
the same speed. Depending on the design, the conveyance can also proceed
in steps.

[0012] The first material can include any imaginable material that can be
deposited layerwise. This could be e.g. a powder material, a film
material or a fluid material, for example a melted extrusion and/or a
dripped material as used with the known Fused Deposition Modeling (FDM)
process.

[0013] If a particulate material is now provided as a first material,
then, according to a preferred embodiment of the present invention, a
method for producing three-dimensional objects could be provided that
uses a three-dimensional printing method based on computer-provided data,
whereby a material is deposited in layers with the aid of a spreader
device in a process chamber onto a particulate material feedstock and the
particulate material is selectively solidified using a solidification
apparatus in the process chamber, those steps being repeated until a
desired object is obtained and unpacked.

[0014] According to a preferred embodiment of the present invention, the
build process includes the application of a first material layer and, if
required, the solidification of certain areas, according to the computer
data provided.

[0015] The conveyance of the first material continuously, sequentially and
uniformly up to an unpacking position including during the build process
enables the continuous and to some degree simultaneous implementation of
multiple work steps. Such a device can also be operated infinitely.

[0016] Whereby conveyance, according to a preferred embodiment of the
present invention, does not mean only the execution of a first material.
It could also well be that the spreader unit and the solidification unit
are moved over the layers of the first material and, consequently, an
area of a process chamber or build-up space and with it also an unpacking
position is constantly shifted and thereby the first material is conveyed
according to kinematic reversal.

[0017] It is thus proposed to dispense with a lowerable build platform
during operation of the method and instead of this to produce a
continuous material layer stack or even a particulate material feedstock,
for example. This material layer stack or particulate material feedstock
with built objects, if applicable, can on one side have already exited a
process space as well as the unpacking position, while on the other side
the build process of objects is still being executed.

[0018] According to a preferred embodiment of the invention, in a method
according to the invention, a conveyance direction essentially remains up
to the unpacking position. According to the invention, this should foe
understood to mean that the conveyance may well exhibit slight direction
changes, such as curves. However, no direction reversal is to take place.
Since the conveyance process is continuous, the conveyance speed also
remains essentially the same.

[0019] According to a preferred embodiment of the invention, it may prove
advantageous if the spreader device, respectively the means for
application for the first material, and a deposited material layer of the
first material are such provided that the means for application and said
material layer are moved toward each other relatively for said
application of a further material layer that a reception plane of the
material layer exhibits an angle of >0° to a layer plane of the
means for application.

[0020] The use of particulate material could e.g. include such that the
spreader device and the particulate material feedstock are such provided
that said spreader device and feedstock are moved toward each other
relatively for application of a further material layer that a reception
plane of a particulate material reception means exhibits an angle of
>0° to a layer plane of the spreader device.

[0021] Especially preferred is the selection of an angle less than or
equal to an angle of repose of the particulate material.

[0022] Depending on the method and manner in which the material is moved
forward, it may be helpful under circumstances if the solidification
apparatus creates structures in the material, especially auxiliary
structures, which hamper the sliding away of material in the process
space. Such an embodiment can yet further stabilize the material layers.

[0023] When using particulate material, the method according to the
invention can preferably be executed in such a way that first particulate
material is introduced in a feedstock in a process chamber and then a
build process of an object begins on this particulate material feedstock.

[0024] According to an especially preferred embodiment of the present
invention, it may be provided that after removal from the process space,
the objects created are e.g. unpacked from the particulate material
without interrupting the build process.

[0025] According to an especially preferred embodiment of the method
according to the invention, solid material is deposited in the form of
thin films.

[0026] These films can, for example, be connected to each other by means
of gluing and/or welding.

[0027] Besides that, it is also possible that the solidification apparatus
creates structures that facilitate the automatic unpacking of the
components.

[0028] By so doing, the method according to the invention can be executed
continuously. That means that a build process of the object takes place
in the layers of the material in a process space or process area and the
material layers are always transported with the objects and the build
process can be carried out infinitely. After conducting the objects out
from the process space area, these can be e.g. unpacked and removed from
any conveyance means if the material is moved according to a preferred
embodiment via a conveyance means. In this regard, conveyance can proceed
either continuously and/or discontinuously.

[0029] For example, it is conceivable that the conveyance runs ad
infinitum.

[0030] It is also possible that the material moves horizontally or
horizontally with an angle.

[0031] According to a further aspect, the invention also relates to a
method for continuously producing three-dimensional objects using
computer-provided data, whereby a material is deposited on a movable
material reception means and on one side of the material an object or
multiple objects are formed by repeated application of layers of the
material and subsequent solidification and/or binding of the material and
repetition of these steps, the object or objects on the material
reception means are continuously moved out of a process area during the
production process and unpacked on the material reception means during
the production process.

[0032] It may prove advantageous if the layer plane exhibits an angle of
>0° to a reception plane of the reception means.

[0033] According to a further aspect of the present invention, a device
for producing three-dimensional objects using computer-provided data is
described. Whereby a material is deposited in layers using a spreader
device and selectively solidified using a solidification apparatus and
these steps are repeated.

[0034] If, for instance, particulate material is used as the layer
material, then it may be provided that such a device deposits particulate
material in layers with the aid Of a spreader device on a particulate
material feedstock and the particulate material is selectively solidified
using a solidification apparatus and these steps are repeated.

[0035] To do so, means are provided to convey the material during the
build process continuously and sequentially up to an unpacking position.

[0036] Moreover, it is conceivable that the material includes film
material, extrusion material and/or a fluid.

[0037] Preferably, it may also be provided that the solidification
apparatus can be a drop generator and/or a radiation source.

[0038] In this regard, a second material can be self-curing, for example,
when coming in contact with the particulate material. Or the particulate
material can be mixed with a substance that leads to the solidification
of the material upon contact. It is also conceivable that the second
material cures by means of UV radiation or supply of heat or in the
presence of a gas.

[0039] According to a further preferred embodiment of the present
invention, the spreader device and/or the solidification apparatus are
moved on a coordinate system arranged at an angle perpendicular to the
reception plane of the reception means.

[0040] If a particulate material is used, then preferably the angle
selected for the coordinate system is smaller than the angle of repose of
the particulate material.

[0041] In so doing, according to an especially preferred embodiment of the
present invention, the angle of the feedstock favors freeing the objects
after the build process by means of sliding off of particulate material.

[0042] According to a preferred embodiment of the present invention, the
material is moved on a conveyor, whereby this may advantageously have one
or multiple conveyor belts.

[0043] Furthermore it also possible that the conveyor has a chain
conveyor.

[0044] In order to design the device somewhat smaller, it can also be
provided that it is provided with limitations of the material layers.

[0045] In this regard and if needed, these material layers can be
stabilized by means of limitation walls on both sides as well as above.

[0046] On the front sides, the layer material or the feedstock (if using
particulate material) are respectively accessible. A spreader device that
deposits new particulate material onto the feedstock is mounted on the
one front side. To do so, the spreader device moves over the feedstock at
the angle alpha to the horizontal, which is less than the angle of repose
of the particulate material. It is thereby ensured that the layer of
newly deposited particulate material remains at the desired site and does
not slip off. The angle alpha can advantageously be adjusted on the
device in order to harmonize this to the particulate material. In
addition, on this side a device is mounted that selectively solidifies
the particulate material alongside the particulate material plane defined
by the spreader device. This solidification apparatus can be a print
head, which releases small fluid droplets on the particulate material
with the result that the particulate material solidifies there in a
locally demarcated manner. Other devices can alternatively be employed,
such as a radiation source for high energy beams.

[0047] After completion of a layer comprised of a coating and subsequent
solidification, the feedstock is further transported a distance
determined by the layer thickness. This can proceed with the aid of a
conveyor belt on which the feedstock rests.

[0048] It would be possible to also design the bordering surfaces on the
sides of the feedstock as synchronous conveyor belts, Examples of other
conveyance options include the use of form-fitting conveyor chains, which
only partially engage with the feedstock, e.g. via adapters, and move
these forward layer thickness by layer thickness.

[0049] Subsequent to completion of the current layer and after the print
head and spreader device have moved into a park position, it is also
conceivable that an assembly line tray be used that comes in contact with
the feedstock and pushes it forward layer thickness by layer thickness in
the direction of the other free end.

[0050] In all its described embodiments, a device according to the
invention is simpler to construct than the described state of technology.
This is due to several points. On the one hand, the quantity of moving
particulate material during continuous operation is nearly constant and
does not increase as is the case with devices of the prior art. That
simplifies guideways and drives since these can be designed for a
constant operating point. On the other hand, the movement of the
particulate material feedstock and the reception of the forces of its own
weight that it exerts are separate from one another. The feedstock rests
on an underlay and does not have to be moved in the gravitational
direction at all or only to a small degree.

[0051] To prevent slipping down of the feedstock, a grid structure can be
printed along with it. This stabilises the particulate material feedstock
and also helps to hinder the uncontrolled discharge of the particulate
material in the break-out zone later on.

[0052] The length of the feedstock from the printing and/or coating unit
right up to the exiting from the process space, respectively, the exiting
from the process space and arrival in the unpacking area, for instance at
a side opposite the process space, can be adapted to the respective
solidification process. The length can be designed in a way that the
feedstock remains a certain retention period in a contiguous situation to
e.g. give the liquid time to react with the particulate material, thereby
developing adequate stability, it is also possible that the
solidification process requires heat or produces heat. Heat could be
introduced by e.g. a pre-heated particulate material or e.g. radiation
sources, which warm the coating plane in which the feedstock is to be
introduced. In this case, the retention period can be used to allow the
feedstock to cool down in a controlled fashion from the side opposite the
solidification zone. There are also conceivable cases where both effects
are jointly used. In both cases, a gradient results that conforms to the
layer-building and passes through the feedstock.

[0053] In contrast to the discontinuous methods, in this case the layers
reach the break-out zone in the same sequence as they were built. The
retention period can thus be held nearly constant in the particulate
material feedstock for all areas. This is a great advantage since in this
way the curing can proceed in a much more controlled manner and is
thereby accompanied by less delay than with devices according to the
state of technology.

[0054] At the second free end, a break-out zone (unpacking position) is
connected, in which unbound parts of the particulate material are
removed. This can proceed manually or e.g. automatically with suctioning
and/or blowing off. In so doing, the break-out zone should be dimensioned
long enough in the layer-building direction that also larger objects can
be completely removed and that interruptions in break-out activities even
lasting longer periods of time do not necessarily have to lead to a
termination of the layer building process simply because the feedstock
reaches the end of the device.

[0055] Since the components can be laid stacked over one another in the
direction of gravity, it may fee required to embed the components with
support structures that also have to be built and that are able to
develop sufficient backing effect even in the absence of surrounding
particulate material and to hold the components in position until they
are removed.

[0056] Moreover, the break-out zone can be designed in such a manner that
a great deal of the unbound particulate material can flow off freely. For
example, this can take the form of a perforated underlay and/or may be
achieved alone due to the absence of the lateral limitation walls.

[0057] The break-out zone can have auxiliary means such as nozzles
pressurized with compressed air or other fluids, which are aimed at the
particulate material feedstock and support the conveying away of unbound
particulate material during operation. The discharge of particulate
material in the break-out zone can also be supported by input of
mechanical energy, such as vibrations, for example.

[0058] If the particulate material is reusable in the process, then it can
be collected in the break-out zone and again fed into the application
process after a possible pass through a preparation section. In the
preparation section, it may also be necessary to perform a sifting of the
particulate material and/or a regulated feed-in of fresh particulate
material.

[0059] In this case, the device has the advantage over the state of
technology in that the application zone and the break-out zone are both
present and united in a single device and the material flows can thus be
executed and controlled easily. Due to the continuous operation, only a
relatively small quantity of particulate material needs to be buffered if
the corresponding particulate material is reused. If reusability of
particulate material is completely implemented, then only a particulate
material quantity corresponding to that of the solidified quantity needs
to be supplied to the process.

[0060] In the case of horizontal orientation of the conveyance plane, the
solidification period, respectively, the break-out period only affects
the length of the device.

[0061] However, the coordinate system of the layer building is not
Cartesian, but rather distorted by the angle of repose.

[0062] In cases of a very small angle of repose of the particulate
material, this can lead to highly distorted building spaces,
respectively, process chambers, which in turn can lead to prolongation of
the process duration required per component. It can therefore make sense
to tilt the conveyance plane at a beta angle in relation to the
horizontal and, by so doing, correctly reset the coordinate system. This
has the additional advantage that the feedstock's own weight acts in the
conveyance direction and thereby reduces the force required to move the
feedstock.

[0063] In this case, the angle of repose in the break-out zone acts
against the gradient conveyance plane. This means that the particulate
material tends to flow out of the solidification zone. In the worst case,
when the angle of repose is the same as the beta angle, the
solidification zone will completely flow out if no countermeasures are
taken, such as provision of printed compartments or a grid or honeycomb
structure.

[0064] In both cases, it is necessary to set an auxiliary plate on the
conveyance plane when starting the system, which enables the application
of the first layers. This auxiliary plate takes over the alpha angle of
repose and is pulled through the solidification zone by the conveyor
until the end of the break-out space is reached and the auxiliary plate
can be easily removed.

[0065] No special measures need to be observed, however, when shutting
down the system. The free end of the feedstock is simply pulled through
the solidification zone into the break-out area.

[0066] Such a system enables the processing of a multitude of different
materials. Besides fluids, film material and extrusion material, possible
materials also include sand, gypsum, metal particulate material or other
inorganic particulate materials as well as plastic particulate material,
flour and other organic particulate materials.

[0067] The system and the process permit a wide spectrum of varied
applications, such as e.g. the manufacture of molds and models for metal
casting as well as the production of components of the most diverse
types. Likewise, an interesting advantage is that the continuous
procedure also allows production of longer components without having to
modify the device.

[0068] In general, its basic principle of essentially running horizontally
in the "Z-axis" makes it suitable for ail solid processing layer
processes. That means that the principle can function anywhere where the
deposited material has already developed sufficient stability shortly
after application so that it does not slide away sideways due to its own
weight.

[0069] According to the present invention, the material application types
can vary. [0070] 1) Solid materials in the form of thin films made of
paper, metal as well as plastic etc. can be applied in layers (LOM). For
example, they can be applied to a layer body, which is essentially moved
horizontally. [0071] The application plane of the layer body can be
positioned at an angle of less than 90° to the movement direction,
but this is not obligatory. In Cartesian coordinate system would make
sense in such a case, meaning that the application plane is situated
perpendicular to the movement direction. [0072] The films are applied
onto the layer body and thereupon connected e.g. by gluing, welding or
similar means. The contour of the component is cut out of the respective
layer by means of e.g. a laser, cutter assembly or other cutting method.
In doing such, the cutting can either take place before or after the
application step. If it takes place after the application step, then the
depth of the cut must be checked. To facilitate unpacking, auxiliary
cutting aids can be employed to divide the surrounding film material into
smaller units. The auxiliary cuts can, for example, be executed in the
shape of rectangles. On complicated structures, the rectangles can be
further reduced in size in order to better access the contour. Another
option for simplification of unpacking is the selective application of
adhesive between the films. For example, this can proceed via the
photoelectric application of a hot melt adhesive (by means of a laser
printer). [0073] The films can either be dispensed from the roll or
transported from a single-sheet supply in the application area. Unrolling
from the roll is advantageous in this context since the automation
expenditure can be kept minimal. [0074] If the current film is applied
and cut, then the infeed is activated and the layer body is further
transported by one layer thickness. The layer body should have reached a
certain length in order to stably store the components located there. If
the layer body has reached this minimum length on the conveyor, then
removal of the excess him can be begun on the end opposite the film
application plane in order to break out the actual components. The
removal can then proceed manually. The advantage of this build-up type
lies in the quasi-infinite operation of the system. [0075] In order to
start up the system, an additional device in the form of an angle is
needed upon which the first layers are applied. The angle is needed until
the layer body being built up with layers acquires sufficient inherent
strength that it can bear its own weight without deforming. [0076] 2)
Hot-melt materials can also be applied to the layer bodies in extruded
form (FDM). Likewise in this case, to start up the system an angle on the
conveyor is needed as an auxiliary platform until the layer body achieves
sufficient stability. For this purpose, an extruded "rope" of a meltable
material is conveyed via any one of the position-adjustable heated
nozzles in the application plane so that a controlled material flow of
the now molten material is created at its outlet. The nozzle is
computer-controlled over the existing layer body and selectively
dispenses material onto the corresponding areas. The material flow must
be coordinated with the nozzle movement in order to guarantee a uniform
extrusion thickness. The underlying structure made out of extrusion
material will melt again during application and will result in a solid
connection together with the new material. The nozzle movement is
controlled via e.g. a system of two crossed spindle axes in the layer
application plane. [0077] So that components of any complexity can be
created, a second material is applied in the same manner via a second
nozzle to the areas that are suitable for supporting the weight of the
desired structure on the conveyance plane. The second material can e.g.
possess a lower melting point than the first material or e.g. have
different solubility characteristics in fluid media. [0078] In order to
avoid delay, the layer body can be built in a heated atmosphere. The
temperature of the layer body, however, should lie below the
solidification temperature of the second material. [0079] The build-up of
the layer body then proceeds in a manner compliant to the method
described under 1), After a certain minimum length, the layer body can be
conducted out of the heated atmosphere via a cool-down section and, for
example, exposed to the dissolving fluid in a removal area, thus
separating the components from the support structures. [0080] It is
likewise feasible to isolate the layer body after exiting from the
cool-down section, e.g. via separation by means of a thermo saw, and then
further process the resulting blocks. The blocks should then have the
lengths of the intended components located therein. [0081] 3) Not least
of all, a layer body can also be created in a similar manner via drip
application of a second material (MJM). To do so, print heads that can
generate individual drops of two different materials are moved in one
layer application plane over the layer body and dispense the build
material and support material corresponding to the contour data issued by
the computer. The support material must again ensure that at least the
layer body's own weight can be supported on the conveyance unit. [0082]
Solidification of the build material can take place thermally via cooling
of a molten mass or likewise via a polymerization reaction, e.g. by means
of exposure to light of a photo-sensitive polymer.

[0083] The same applies to the support material.

[0084] In all three cases, the control of the thickness of the layer
currently being processed represents the real challenge. In case 1), this
cannot be adjusted since the thickness is determined by the film used. It
is therefore advisable to measure the glued-on material thickness. The
measurement can be used to calculate a correction of the forthcoming
layer data and to compensate for previously resulting errors.

[0085] In cases 2) and 3), the application height can be checked by means
of an additional leveling element, such as the surface of the nozzle in
2) or a heated roller or a scraper blade or a cutter.

[0086] A method according to the invention can be implemented more simply
than a method on devices of the state of technology.

[0087] In contrast to devices according to the state of technology, the
movement of the device for layer positioning must not proceed rapidly
because positioning runs with long paths are no longer needed. A
consequence, of such is that a discontinuous switching device may also be
used. This involves moving one layer thickness after a spreading process.
One example could be a pneumatic actuator. The layer thickness is
controlled by means of end stops. Levers or gears can be used to
translate the movement. Especially preferred is an indexing clutch in
combination with a lever that is actuated by means of a pneumatic
cylinder.

[0088] For the purpose of more detailed explanation, the invention is
described in further detail below on the basis of preferred embodiments
with reference to the drawing.

[0089] In the drawing:

[0090] FIG. 1 An isometric view of a device according to the state of
technology;

[0091] FIG. 2 A sectional view of a device according to the state of
technology;

[0092] FIG. 3 A sectional view of a build chamber according to the state
of technology and an illustration of various component stabilities;

[0093] FIG. 4 A sectional view of a preferred embodiment of the invention;

[0094] FIG. 5 An illustration on the angle of repose and the transference
to a preferred embodiment of the invention;

[0095] FIG. 6 An isometric view of one preferred embodiment of the
invention;

[0096] FIG. 7 A sectional view of a further preferred embodiment of the
invention;

[0097] FIG. 8 An illustration of possible error sources of devices
according to the invention;

[0098] FIG. 9 A sectional view of a preferred embodiment of the invention;

[0099] FIG. 10 A sectional view of a further preferred embodiment of the
invention;

[0100] FIG. 11 A sectional view of a further preferred embodiment of the
invention for the automatic unpacking of the components;

[0101] FIG. 12 An isometric view of a device according to the invention
for the automatic removal of particulate material;

[0102] FIG. 13 A sectional view of a device according to the invention;

[0103] FIG. 14 A plate link belt as conveyance means for the usage
according to a preferred embodiment of the invention;

[0104] FIG. 15 A magazine belt as conveyance means for the usage according
to a preferred embodiment of the invention;

[0105] FIG. 16 A perspective view of a method according to a preferred
embodiment, which uses film as material;

[0106] FIG. 17 A perspective view of a method according to a preferred
embodiment, which uses melted plastic as material;

[0107] FIG. 18 A perspective view of a method according to a preferred
embodiment, which uses a print head to apply build material;

[0110] FIG. 1 shows a device according to the state of technology. A
spreader device (2) applies a layer consisting of particulate material on
a build platform (3). At the conclusion, with the aid of
computer-provided data, the particulate material is selectively
solidified to a component (4) using the solidification apparatus (1), in
this case a print head. The vertical direction or also the direction of
gravity, which is depicted here perpendicular to the build platform (3),
is designated with arrow (5). After solidification the build platform (3)
is lowered by one layer thickness and then another layer is created.

[0111] In FIG. 2 the same device is depicted in sectional view. Several
layers have already been created. A limiting factor during the method
according to the state of technology is the build chamber depicted in the
figure as (7), which is in this case also the process chamber. After a
certain build height (6), the chamber (7) must be emptied or exchanged.

[0112] If the solidification is not immediately effected, but rather with
a certain time delay, then special circumstances are to be taken into
consideration with the method according to the state of technology.

[0113] As an example that can be derived from FIG. 3, during unpacking of
component (4), the parts that were last created by the solidification
apparatus (1) and the spreader device (2) are located above in the build
chamber (7). These parts (8) are less solid than the parts (9) and (10)
located further below in the build chamber (7). This necessitates a
minimum waiting time that must be complied with before unpacking during
such a process.

[0114] FIG. 4 depicts the first of the preferred embodiments of the
invention. FIG. 4 shows a sectional view comparable with FIG. 2. The
method sequence is subdivided into sub-steps, namely, commissioning of
the device, continuous production of components (4) and shutdown of the
device. These phases are described in the following:

Commissioning

[0115] Creation of a basic feedstock--The spreader device (2) applies one
layer comparable to that shown in FIG. 1. The layer plane of the
particulate material, however, which, with the state of technology,
corresponds to a plane that is parallel to the build platform (3), is
inclined at an angle a in relation to a conveyor belt (11) here.

[0116] This coating process is repeated until sufficient filling is
present to obtain the desired dimensions for component (4) being
manufactured. In this manner a feedstock results, which is smooth on the
spreader device side and fissured on the opposite-facing side in
accordance with the particulate material properties.

Continuous Build Process

[0117] If a basic feedstock is created, then a continuous build process
can begin that only requires termination when the device is stopped for
maintenance purposes. The process is designed to a great degree along the
lines of the state of technology.

[0118] In a process chamber the spreader device (2) creates a layer that
forms an angle α in relation to the perpendicular (5). At the
conclusion, a predetermined quantity of particulate material is
selectively solidified using the solidification apparatus (1). The
process chamber is in this sense not a delineated room, but rather the
space in which the object is built; the object is subsequently removed
from this area, respectively process chamber.

[0119] The computer data processing must take this arrangement into
consideration. The conveyor belt (11) is thereafter moved one layer
thickness further so that the feedstock moves out from the spreader
device plane and hereby gradually moves out of the process chamber. This
process repeats itself until the device is shut down. Located in the
feedstock are the components (4), which are ever further removed from the
spreader device plane by the infeed movement.

[0120] After a certain distance on the conveyor belt (11), the components
can be unpacked, while the build process continues uninterrupted in the
process chamber. The length of this distance of the conveyor belt (11)
hereby depends on the process employed. For instance, cooling is relevant
when dealing with sintering processes. The curing time is relevant in
cases of chemical solidification mechanisms.

[0121] In addition, the ejection of components (4) and the unbound
particulate material from special areas may proceed in this area, such
as, for example, protective gas atmospheres.

[0122] The unpacking itself can take place manually on the device or via
discharge of the particulate material.

Shutting Down

[0123] If the device is to be shut down for maintenance purposes, the
entire feedstock can be brought on the conveyor belt (11) and out of the
process chamber by moving the conveyor belt (11).

[0124] The angle (13) between the conveyor belt (11) and the spreader
device plane is limited by the angle of repose of the particulate
material (FIG. 5). Since an angle greater than the angle of repose (12)
is accompanied by an increased risk of particulate material sliding off,
the angle selected should be smaller than the angle of repose (12). In so
doing, it can be guaranteed that a perfect surface is always available
for the build process.

[0125] FIG. 6 shows an isometric view of an especially preferred
embodiment of the invention. Here can be seen the walls (14) mounted for
lateral delimitation of the feedstock. The feedstock runs through and is
subjected to frictional forces. These wails enable the device, at the
same usable cross-section, to be built smaller than if the particulate
material were allowed to laterally flow freely. Outside of the process
chamber, the walls (14) can be dispensed with so that a portion of the
work required for unpacking the components, namely removal of unbound
particle material, can be carried out by allowing the particulate
material to freely run off (15) by simply leaving these wails (14)
absent.

[0126] FIG. 7 shows another preferred embodiment of the invention. The
illustration shows a sectional view. The conveyor belt (11) is inclined
at a certain angle in relation to the perpendicular (5) here. Viewed
horizontally, the plane on which the spreader device (2) and the
solidification apparatus move now lies flatter than with the initially
described device. On such an embodiment of the invention, particulate
materials that exhibit a shallower angle of repose can also be
economically processed. The steeper angle in the unpacking area does not
disturb because a smooth surface area is hot required here. The angle
also favors the self-actuating unpacking of components (4).

[0127] If the angle of repose (12) is exceeded by the device according to
the invention, then the smooth surfaces in the particulate material areas
(18) created by the spreader device (2) break out so that no defined
surfaces exist any longer for the solidification process. One method to
address this problem is described in the following:

[0128] Another preferred embodiment of the invention is shown in FIG. 9.
Protective structures or auxiliary structures (19) are created via the
solidification apparatus (1). These artificially increase the angle of
repose (12) of the particulate material. By so doing, "difficult"
particulate materials can also be processed without modification of the
device. The horizontal surfaces shown can be used for this purpose.
However, there is no limit placed on usage of other structures, which
could exhibit nearly any three-dimensional structure.

[0129] FIG. 10 shows the above-described devices with the same
corresponding arrangement. In this case, the material extrudate is
discharged parallel to the perpendicular. So that the feedstock created
by the spreader device (2) does not slip away, plates, represented by
floor plates (20), are built by the solidification apparatus (1). These
engage with at least two conveyor belts. The remaining walls can be
implemented rigidly for delimitation of the particulate material
feedstock. Shown below the actual device is another transfer conveyor
belt (22) that enables a continuous production process as described in
claim 1. The feedstock is taken over here and the components (4) can be
removed as the device continues to produce.

[0130] The described continuous production principle is also suitable for
the construction of an entirely automated production system. This is
represented in FIG. 11. In order to enable a robot (24) to grip the
components (4), the option exists to attach auxiliary structures (23)
with the solidification apparatus, thus facilitating grasping by the
robot (24). The position of the components (4) in the feedstock is known
from the production principle and can be used for the control of the
robot (24).

[0131] FIG. 12 shows a preferred embodiment of a conveyor belt (11) to
move the feedstock. The conveyor belt (11) itself contains openings (26).
Beneath the conveyor belt (11) is a guidance plate (25). This bears the
weight of the feedstock and guarantees the accuracy of feedstock
movement. The guidance plate (25) has no openings in the area in which
the feedstock is created and in the area in which components (4) are
subsequently solidified. In the unpacking area, the openings (26) and
(27) correspond depending on the position of the belt (11). A portion of
the particulate material thus runs off by itself and exposes the
components (4).

[0132] FIG. 13 shows that with a device according to the invention even
components (4) that have very large sizes in one dimension can be
produced. Such components must merely be supported if they are longer
than the actual size of the device. To this end, additional simple
conveyor belts (28) can be provided that take over the component or
components (4) at the end of the device.

[0133] Further conveyance means are depicted in FIGS. 14 and 15, showing
how according to the invention they could be used instead of a conveyor
belt.

[0134] A plate-link belt is shown as a conveyance means in FIG. 14, while
FIG. 15 shows a magazine belt. Plate-link belts have proven to be
advantageous conveyance means since they can receive heavier loads than
e.g. fabric-based belt conveyors and they additionally exhibit greater
rigidity perpendicular to the conveyance direction. In FIG. 14, two
various plate-link belts are depicted, which have linked plates (29). The
build space (7) could be provided with such conveyance means for objects
e.g. in the dashed line area.

[0135] The use of magazine belts (see FIG. 15) in a device according to
the invention proves advantageous if, in addition to high rigidity,
modularity is also required in the conveyor chain. With the aid of such
magazine belts, e.g. printed objects can remain on the respective section
of the conveyor line, for instance, on the build platform (31), until
further use in a magazine (32) after completion of the build-up process
and in this manner be separated temporarily from the remaining conveyor
chain. The conveyor length can also be relatively freely adapted to the
requirements and local conditions by simply either adding additional link
plates (31) in the magazine (32) or removing them from there. This can
take place e.g. using a cylinder (30), which pushes a link plate out of
the magazine and then moves this forward over the conveyor rollers (33).
One possible arrangement of a build space (7) is shown again as a dashed
line drawing.

[0136] FIG. 16 shows a method according to a preferred embodiment of the
invention. In this case, this is an endlessly continuous process for
generative manufacturing methods, in which film layers (34) with cut-out
contours are glued to a model (35).

[0137] The film layers can be thin rolls (38) made of paper, metal as well
as of plastic. They are applied on a workpiece being run (36), which is
moved essentially horizontally on a conveyor belt (11).

[0138] The application plane of the layer body proceeds with an angle less
than 90° in relation to the movement direction.

[0139] The films (34) are applied onto the layer body and thereupon
connected by means of e.g. gluing, welding or similar means. The contour
of the component is cut out of the respective layer e.g. with a laser
(37). The cutting can either take place before or after the application
step. If it fakes place after the application step, then the depth of the
cut must be checked. To facilitate unpacking, the aid of a hot-wire saw
(39) can be employed for auxiliary cuts, which divide the surrounding
film material into smaller units. The auxiliary cuts can, for example, be
executed in the shape of rectangles. On complicated structures, the
rectangles can be further reduced in size in order to better access the
contour.

[0140] If the current film layer (34) is applied and cut, then the infeed
is actuated and the layer bodies are further transported by one layer
thickness. The layer body should have reached a certain length in order
to stably store the components or models (35) located there. If the layer
body has reached this minimum length in the conveyor direction (11), then
removal of the excess film can be begun on the end opposite the film
application plane in order to break out the actual components. The
removal can then proceed manually. The advantage of this build-up type
lies in the quasi-infinite operation of the system.

[0141] In order to start up the system, an angle or workplace (36) is
needed upon which the first layers (34) are applied. The angle is needed
until the layer body (35) being built up with layers acquires sufficient
inherent strength and can bear its own weight without deforming.

[0142] FIG. 17 depicts a perspective view of a method according to a
preferred embodiment, which uses melted plastic as material in nozzles
(42).

[0143] According to the embodiment shown, another nozzle (43) is provided
for the application of support material (44). The whole unit is thereby
moved forward again on a conveyor belt (11). Since such a method forms an
endless block, the finished part areas must be separated for removal, for
example, by means of a hotwire saw (39).

[0144] The print heads (42, 43), which can generate individual drops of
two different materials, are moved in a layer application plane over the
layer body (35) and dispense the build material and support material (44)
corresponding to the contour data issued by the computer. The support
material (44) should hereby ensure that at least the layer body's (35)
own weight can be supported on the conveyance unit (11).

[0145] An endlessly continuous method for a 3D printing process, during
which the material is directly deposited with a print head (45), is
depicted in FIG. 18.

[0146] A device used to accomplish this can be simplified for such a
method.

[0147] In contrast to devices according to the state of technology, the
movement of the device for layer positioning must not proceed rapidly
because positioning runs with long paths are no longer needed. As
mentioned above, a consequence of such is that a discontinuous switching
device may also be used. Possible embodiments are depicted in FIG. 19 and
FIG. 20.

[0148] A powder feedstock (46) is provided on a conveyor belt (11).

[0149] In order to move one layer thickness after a coating process, the
entire conveyor belt is moved in such a manner using the drive roller
that the application plane approaches the drive roller as per the desired
layer thickness. The torque required for this and the angle of rotation
can be applied using a lever (48) that is connected with a drive roller
via an overrunning clutch (47). The lever can be e.g. actuated by means
of a pneumatic cylinder (49). The layer thickness itself is then
specified by the travelling distance of the cylinder. This can be
delimited by end stops.

[0150] Other gear stages (51) may make sense depending on the required
torque moments required, The layer thickness due to elasticity and
slackness can be determined during commissioning and the desired target
layer thickness can be set.